Polyaniline, one of the most promising intrinsically conducting polymers, has received considerable attention in recent years due to its straightforward polymerization, chemical stability, relatively high conductivity and potential applications in electronic devices, batteries and sensors. A major breakthrough in the field was the discovery of self-doped polyaniline due to its desirable properties. For example, the self-doped form of polyaniline has several advantages including better solubility as well as redox activity and conductivity over a wider pH range. However, there are a number of tradeoffs including reduced mechanical stability (especially in the presence of good solvents) and decreased conductivity due to steric effects. Ideally, it should be possible to switch between self-doped and non-self-doped states so that the properties of the polymer can be manipulated to achieve desired properties during synthesis, processing, and finally use of the polymer.
Herein we report a novel approach to the creation of a substituted polyaniline whose self-doped state can be controlled via complexation between boronic acid groups along the backbone with D-fructose in the presence of fluoride. For the first time, this allows the formation of a water-soluble, self-doped conducting polymer under the polymerization conditions. In turn this facilitates the growth of polyaniline over a wider pH range. This has important implications toward synthesis (yield, molecular weight), processing (controlled precipitation), and implementation (extended pH range).